1. Field of the Invention
The invention relates to the field of devices for controlling the attitude of a vehicle, such as a satellite.
2. Description of the Prior Art
Angular momentum exchange control is ideal for space applications because it can be powered from transformed solar energy and which, therefore, is more applicable to long life missions than one relying solely on stored fuel or cold gas storage. Prior art designs of angular momentum exchange devices, however, have a life limited by wheel bearings and lubrication. Magnetic bearings have been proposed in the prior art, such as for example U.S. Pat No. 3,490,816 to Lyman, suggesting a journal bearing design, wherein the assembly consists of two such bearings suspending a shaft with a flywheel between the bearings. The volumetric efficiency of such approach is not optimal and balancing is a dynamic as well as a static problem.